input = int(raw_input())
sosu = [2,3,5,7,11,13]
gouseisu = [4,6,8,9,10,12]
count = 0
num = []

for s in sosu:
	for g in gouseisu:
		num.append(s*g)

for n in num:
	if n == input:
		count +=1

output = float(count)/36

print output